Thanks for the responses, sorry I've taken so long to get back. Reasons for 12V upgrade: I could dispense with the 9 inch flywheel I have been using since I got the truck (someone had put in a 1942 216 flywheel with a matching 6 volt starter). We put in a fresh rebuilt 235 1956 motor during the 12V upgrade and the core we found came with a 10 inch flywheel but it was for 12V (168 or so teeth versus the 139 or so of the 6V). Finding a 10 inch 54 6V flywheel just seemed like more trouble than I needed. Also there were still charging issues with the 6V despite all new or rebuilt charging and starting system and despite too, having ground strapped everything but my mother when she went for a ride in it...and still the battery would get weak and headlights dim.
Here's the exciting part: my buddy and I decided to store the 6V distributor with the 6V electronic ign module for a rainy day, and re-use points and cond. with the 6V coil and a ballast resistor from a 79 to 86 Dodge product (part# AL125DCS). I thought I should get a 12V universal coil (for use with external resistor) to be on the safe side. When I hooked up the 12V coil, NOTHING. NADA. Wouldn't run at all. When I re-hooked up the 6V coil and 12V resistor in the new 12V system ... MAGIC! It ran like a champ. We took the truck on a 200 mile break in run and had zero problems with the cheap Wal-Mart 12V battery, Dodge 12V ballast resistor/6V coil and 6V points/condensor arrangement.
There was one problem: we hit the mountains in a blizzard and still had the 6V blower motor in the heater...
scraping ice off the INSIDE of a windshield in unpleasant.
One more thing, a voltage meter across the resistor to ground when engine running shows 12 volts out to coil. So the Dodge resistor is only dropping the volts by about 2. Weird. But I cannot argue with success. I have another 6V coil in the event this one takes a dump. So far it neither heats up unusually nor stalls out.
...BTW, 12V halogen headlights are excellent for brightness! We'll probably not be using 6 volt again. If anybody needs a slightly used rebuilt 9 inch 6 volt pressure plate and flywheel, recently rebuilt generator and starter and new regulator with probably less than 5,000 miles on them, let me know.
I have to figure out a voltage drop transistor circuit for the original 6 volt radio. Resistors don't really work.
